In a resinous shroud described in JP-A-10-238825, a casing used as a container of an air cleaner and a shroud ring portion for holding a fan are integrally formed to be adjacent each other.
When the resinous shroud including the air cleaner casing is molded using a resin material, a gate portion for filling the resin material is disposed at a center portion of the shroud ring portion and at a predetermined end portion of the air cleaner casing. The resin material flowing to a molding die of the casing from the center portion of the shroud ring portion joins windingly the resin material flowing in the molding die of the casing in one direction so that welds generate at a junction. The larger a quantity of the resin materials joined from two directions becomes, the bigger welds generates. Thereby, deformation such as cambers generates in the casing after the shroud was formed. By such the cambers in the casing, the casing is difficult to be fitted to an air cleaner element and/or a cover member, and thereby it becomes difficult for an appropriate assembling and a sealing to be performed.